1. Field of the Invention
The present invention relates to a vibration control device used between fixed and vibrating members and more particularly to an improved control member and a bracket integrally formed with a mounting stabilizer portion for damping vibration and to ease assembly.
2. Description of Related Art
A conventional vibration control device, which is mounted between a vibrator, such as engine, and a chassis or body of a vehicle, is shown in FIG. 1. A similar vibration control device is disclosed in U.S. Pat. No. 5,018,699.
As shown in FIG. 1, a vibration control device 70 has a vibration control body 20, a mounting bracket 10, which connects the body 20 to a vibrator side member, such as engine, and a stabilizer 30 which serves to damp large vibration movements of control body 20.
The vibration control body 20 comprises an insulator 230, made of anti-vibration rubber material, an upper plate 250 fixed on the top of the insulator 230 and a relatively large size bolt 50 fixed to the upper plate 250. A stopper portion 220 is integrally formed with the insulator 230. The upper plate 250, bolt 50 and nut 40 are used to join the control body 20 to bracket 10.
Bracket 10 comprises a stay portion 110 and provides an interconnection to the engine, and a flange portion 150 which is joined with the upper plate 250 and a separate stabilizer 30.
When bracket 10 is joined to the vibration control body 20, through the flange portion 150 and the upper plate 250, the separate independent stabilizer 30 will co-operate with the stopper portion 220 to damp large movements of body 20.
Because of the bolted joint between the bracket 10 and the body 20 of the conventional vibration control device 70 and the presence of the independent stabilizer 30 mounted between flange 150 and the upper plate 250, assembly becomes complex.
However, some attempts have been made to resolve the above assembling problems, for example, in Japanese Patent Laid-open publication No. Hei 5-44770.
This reference discloses that an elastic body, such as rubber, has either a concave portion or convex portion and the connecting portion of a bracket or a vibrator has an opposite shape for mating purposes so that the mating members are connected to each other without adhesive. Therefore, when the bracket is connected to the elastic body, the assembling work of the vibration control device is finished.
However, stress in the vibration control device in this reference may be concentrated at the connecting portion so that the rubber portion may fatigue or otherwise fail.
Also, if the vibration control device is a hydraulic type, the liquid may leak out.
Further, it is also possible to reduce the connecting force between the mating portions by abrading the surface of the rubber body.
According to the conventional vibration control device shown in FIG. 1, when the vibration control body 20 moves or vibrates over a wide range of magnitudes, that movement is stopped by the cooperation of stabilizer 30 and the stopper portion 220. However, since stabilizer 30 is an independent member and connected with bracket 10 along with the upper plate 250 by bolt 50 and nut 40, there was a need to reinforce the joint portion. Therefore, the thickness of the flange portion 150 might have to be increased which adds to the cost of the unit.
Consequently, there remain problems such as increased weight, increased volume, the need for additional space, an increase in the number of parts and greater assembly time.